Field of the Invention
The invention relates to a data entry and/or operating system, particularly a keyboard, as well as a POS keyboard, for use under harsh environmental conditions, i.e., a keyboard with higher levels of protection or a keyboard that satisfies the higher levels of protection, particularly higher temperature requirements, in addition to vibration, shock, ESD, etc.
Description of the Background Art
Keyboards that are dustproof and waterproof are already available. Thus, DE 20 2007 003 350 U1 describes a dustproof and waterproof keyboard with an outer covering that is completely sealed and for its part possesses antimicrobial properties. DE 20 2010 008 809 U1 discloses a waterproof keyboard with an LED backlight. In this case, a keyboard plate, forming a plurality of keys, is made as a single piece and is airtight and waterproof. To equalize the air pressure, the base plate of the keyboard has at least one air hole for equalizing the air pressure. DE 60 2004 011 111 T2 (EP 1 697 952 B1), which corresponds to U.S. Pat. No. 7,723,631, published a further waterproof keyboard.
Such airtight keyboards very often have the disadvantage that at temperatures below the freezing point they tend to form condensation water in the interior because of the enclosed air moisture. Further, such keyboards tend to swell at temperatures >50° C.